Fitzpatrick injured his knee during the third quarter of the Jets' 27-23 loss at Miami on Sunday. The quarterback left for a series and was replaced by Bryce Petty, but he returned and finished the game while wearing a brace on the knee. It was heavily wrapped when he spoke to the media afterward.
Fitzpatrick had been benched in favor of Smith against the Ravens after throwing 11 interceptions in the first six games, but he regained his starting role when Smith got hurt.
Petty is now the backup to Fitzpatrick after Geno Smith suffered a season-ending knee injury against Baltimore two weeks ago.
Williams is tied with Marcus Gilchrist for the team lead with two interceptions this season. He led the Jets last season with six interceptions and has played 75 percent of the defensive snaps as a key part of Bowles' defense.
"If he misses a significant amount of time, then Bryce will play," Bowles said. "I mean, he'd have to practice some on Friday, at least, and have a good understanding of the game plan and we'll make a decision going forward."

Petty was a fourth-round pick in last year's draft out of Baylor. He injured his right shoulder in the preseason finale and was unavailable during the first few weeks of the regular season.
NEW YORK (AP) — Ryan Fitzpatrick's grip on the Jets' starting quarterback job all depends on his injured knee,Wholesale Jerseys Free Shipping.
Fitzpatrick's struggles have continued, however, including throwing two interceptions against the Dolphins. That has some fans and media clamoring for the Jets to give Petty a chance at starting.
"We'll know more as the week progresses,Wholesale Jerseys USA," Bowles said during a conference call. "I've got to see him run around a little bit on Wednesday and Thursday first."
Bowles also announced that cornerback Marcus Williams has a high ankle sprain that could sideline him for multiple games.
Coach Todd Bowles announced Monday that Fitzpatrick is "day to day" with a sprained left knee and that his status for New York's game Sunday against the Los Angeles Rams is uncertain.
"We're down, not out right now,Wholesale Jerseys, and I'm not worried about turning the page,Cheap Jerseys From China," Bowles said. "I'm worried about who gives us the best chance to win, and right now Fitz gives us the best chance to win — if he's healthy. If not, then Bryce will get his shot to play."
"Yeah, he'll be ready," Bowles said of Petty,Cheap NFL Jerseys China, who was 2 of 2 for 19 yards in his first regular-season action.
While the injury is not believed to be serious, Bowles says Petty would start Sunday if Fitzpatrick is not healthy enough.